Features of Gas Exchange Surfaces (Cambridge (CIE) IGCSE Biology)

Revision Note

Lára Marie McIvor

Written by: Lára Marie McIvor

Reviewed by: Lucy Kirkham

Did this video help you?

Features of gas exchange surfaces

  • All gas exchange surfaces have features in common

  • These features maximise the rate of gas exchange taking place; they include:

    • Large surface area to allow faster diffusion of gases across the surface

    • Thin walls to ensure diffusion distances remain short

    • Good ventilation with air so that diffusion gradients can be maintained

    • Good blood supply to maintain a high concentration gradient so diffusion occurs faster

The alveolus is the gas exchange surface in humans, IGCSE & GCSE Biology revision notes

The alveolus is the gas exchange surface in humans

Examiner Tips and Tricks

You may notice that several of the features of alveoli that aid their function are the same as those that make villi, or root hair cells, suited to their function, e.g.

  • large surface area

  • good blood supply

  • steep concentration gradient

These structures are all examples of exchange surfaces; they allow the efficient movement of substances across their surface by diffusion, active transport and/or osmosis. So, if you learn the features of one exchange surface, you also know the features of the others!

Last updated:

You've read 0 of your 5 free revision notes this week

Sign up now. It’s free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Lára Marie McIvor

Author: Lára Marie McIvor

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

Lucy Kirkham

Author: Lucy Kirkham

Expertise: Head of STEM

Lucy has been a passionate Maths teacher for over 12 years, teaching maths across the UK and abroad helping to engage, interest and develop confidence in the subject at all levels.Working as a Head of Department and then Director of Maths, Lucy has advised schools and academy trusts in both Scotland and the East Midlands, where her role was to support and coach teachers to improve Maths teaching for all.